Sand mulling apparatus



5 Sheets-Sheet 1 Original Filed May 8, 1963 //VVN7'OR W/LL AQM A. HUNTER flTTORNEY June 21, 1966 w. A. HUNTER SAND MULLING APPARATUS 5 Sheets-Sheet 2 Original Filed May 8, 1963 INVENTOR. VV/LLMM I4. HUNTER BY/ ATTORNEY June 21, 1966 w. A. HUNTER 3,

SAND MULLING APPARATUS Original Filed May 8, 1963 5 Sheets-Sheet 3 Me i INVENTOR. W/L LIAM 4. HUN TEE ATTORNEY June 21, 1966 w. A. HUNTER 3,256,573

SAND MULLING APPARATUS Original Filed May 8, 1963 5 Sheets-Sheet 4 INVENTOR.

W/LL IA M A HUNTER BY I M ATTORNEY United, States Patent SAND MULLING APPARATUS William A. Hunter, Morton Grove, Ill., assignor to Pettibone Mulliken Corporation, Chicago, IlL, a corporation of Delaware Continuation of application Ser. No. 278,972, May 8,

1963. This application June 17, 1965, Ser. No. 464,818 26 Claims. (Cl. 2289) The present patent application for original United States Letters Patent is a continuation of original patent application Serial No. 278,972, filed by me on May 8, 1963, and entitled, Sand Mulling Apparatus, now abandoned.

The present invention relates in particular to an apparatus for mulling or conditioning foundry sand of the type that is used in connection with metal casting operations.

It has long been foundry practice after a casting operation to remove the packed and heated sand from the flasks and then, in order again to condition the sand for reuse in the flasks, to mull the sand by placing it, together with a suitable bonding material, in a large-sized, cup-shaped receptacle and subjecting it to the action of rotary mulling elements and deflector-like plows. -The mulling operation serves to break up any lumps in the sand and, in addition, serves to aerate and resultantly to cool the sand and also to mix the bonding material intimately with the sand. During the mulling operation, water is added to the sand in order to moisten it, thus increasing the bonding strength of the sand when it is ultimately used in a casting operation.

The addition of water to the sand and the aeration of the sand are factors which are of extreme importance in any standard or conventional sand mulling apparatus. The addition of water in the proper amount controls the permeability of the sand when it is used ina casting operation. If the sand is too wet, its permeability will be reduced so that the gases generated by the molten metal cannot escape through the packed sand in the flask, and as a consequence, blown castings result. If the sand is too dry, it will crumble when contacted by the molten metal with the result that an imperfect or unusable casting results. It is, therefore, obvious that the amount of water which is added tothe sand in a mulling apparatus is critical. In foundry practice, molding sand is repeatedly used for casting or molding purposes and, because of the high temperature which the sand may attain after being subjected to successive contact with the molten metal, it is difficult for the operator of a mulling apparatus to control or regulate properly the amount of water which is added during the mulling operation. To obviate this difliculty, it has recently been the practice to subject the sand in the mulling apparatus to forced aeration by the introduction of air in large volume and under pressure into the bowl of the mulling apparatus for sand-cooling purposes. By such an expedient, it is possible to reduce the temperature of the used mulling sand to about 25 degrees above room temperature to the end that excessive evaporation of moisture will not take place and the operator may properly regulate the flow of water into the relatively cool sand by reason of a consistency or uniformity of temperature range of the successive batches v to be mulled or conditioned inthe apparatus.

It follows, therefore, that the efliciency of any sand mulling apparatus is largely dependent upon the ability of the apparatus to effect intimate mixing of the sand, the bonding agent, and the water in the proper amounts and in a batch cycle of minimum duration. A batch cycle may be said to be complete when each grain of sand becomes completely covered with a skin of the bonding agent and thus coated grain has adhered thereto the Patented June 21, 1966 proper amount of moisture with little or no excess or free bonding agent or water being present within the mulling chamber or bowl of the mulling apparatus. The attainment of this condition in the shortest possible period of time .is the aim of a present-day mulling apparatus. It is, therefore, a principal and general object of the present invention to provide a mulling apparatus of the type under consideration, i.e., an apparatus em ploying rotary mulling elements and deflector-like plows which is so designed and constructed that the duration of a batch cycle is materially shortened without any sacrifice in uniformity of sand treatment to the end that the apparatus will, during the course of a days operation, efficiently and effectively mull or condition a greater quantity of used molding sand than has been possible in connection with use of any previously-designed mulling apparatus employing aeration and the addition of water for sand-cooling purposes and permeability control.

In carrying out the above-mentioned object, the invention contemplates the provision of an improved mulling apparatus embodying a cylindrical mulling bowl and a rotary power-driven sand 'mulling assembly within the bowl. The sand mulling assembly of the apparatus includes the usual centrally disposed hub or crosshead with revolving and freely rotatable mulling elements or wheels thereon and, in addition, deflector-like plows which are fixedly secured to the hub for travel in a circular path within the bowl. The centrally disposed hub or crosshead and the mulling wheels are of novel design in that they are shaped or streamlined to follow the natural trajectory of sand resting on a rotating body to the end that they are self-cleaning upon rotation thereof. Stated otherwise, the hub and wheels are so designed that, during rotation thereof, the angle of repose of sand on any given location or point thereof will approximate a zero angle, thus offering practically no frictional opposition to outward flinging of the sand therefrom. This self-cleaning feature constitutes one of the principal features of the present invention.

Another and important object of the invention is to provide a sand mulling apparatus of the aforementioned type and in which the hub, the plows and the wheels are so disposed with respect to one another that the plows, in following their circular path of revolution above the vertical axis of the hub, establish voids in the mass of sand within the mulling bowl; the hub is so designed that it establishes generally radial water-distribution channels in register with the aforementioned plow-created voids so that regulated quantities of water are introduced into the voids; and the rotating wheels, which turn at high velocity due to induced rotation caused by frictional differentials, enter the voids and fling the water into intimate contact with that portion of the sand that is sparsely distributed throughout the voids.

A further and related object of the invention is to provide in a sand mulling apparatus of the type and character under consideration, a novel means for introducing air into the sand within the mulling bowl, some of the air entering the bowl and passing through the radial waterdistribution channels so that the water is, at least in part, air-borne to the voids, and some of the air passing through separate air channels which are established by reason of generally radial vanes on the underneath or bottom surface of the rotating hub of the mulling assembly, this latter air penetrating the sand at regions between the aforementioned voids.

In carrying out the above mentioned objects of the invention, the net effect of the particular air and water introduction into the mulling bowl and of the particular hereinafter specified shape characteristics of the hub, the plows, and the wheels of the rotary mulling assembly is to produce within the upper peripheral region of the mulling bowl, a rotating torus of sand with localized whirls or eddy currents of sand within the torus, the torus being fed with moistened aerated sand from the plow-created voids therebeneath and serving to maintain the moistened sand in a high state of prolonged agitation throughout the entire duration of the batch cycle with no quiescent regions within the bowl for settling-out or accumulation of sand.

A still further object of the invention is to provide in a sand mulling apparatus of the type under consideration a hub mounting and driving structure embodying a tortionally flexible drive shaft for the rotating hub so that sudden shocks which may be encountered due to foreign objects within the mulling bowl may be assimilated by limited but temporary yielding of the shaft A similar and related object of the invention is to provide in a mulling apparatus of the aforementioned character, a frangible driving connection between the tortionally flexible drive shaft and the hub of the rotary mulling assembly, such connection being designed for complete rupture or fracture in the event jamming of the hub should take place or occur.

Other objects and the various advantages of the invention will be readily apparent from a consideration of the following detailed description.

In the accompanying five sheets of drawings forming a part of this specification, one illustrative embodiment of the invention has been shown.

In these drawings:

FIG. 1 is a sectional view taken substantially centrally and vertically through a mulling apparatus constructed according to the principles of the present invention, certain of the parts being shown in elevation and other parts being broken away in order more clearly to reveal the nature of the invention;

FIG. 2 is a top plan view of the improved mulling apparatus;

FIG. 2a is an enlarged horizontal section through that part of the apparatus that has the door-closed sand discharge opening;

FlG. 3 is an enlarged fragmentary sectional view taken on the line 33 of FIG. 1 and limited to the details of a pedestal and hub assembly which are employed in connection with, and form a part of, the invention;

FIG. 4 is an enlarged bottom perspective view of the hub, the plows, and the mulling wheels of the rotary mulling assembly of the apparatus;

FIG..5 is a sectional view taken substantially centrally and vertically through one of the mulling wheels and illustrating its particular manner of connection to the hub;

FIG. 6 is a sectional view taken on the line 66 of FIG. 3; and

FIG. 7 is a graphical representation of a paraboloid of revolution involved in defining certain hub and wheel contours according to the invention.

Referring now to the drawings in detail, the apparatus which is shown therein constitutes one exemplary form of the invention although not necessarily the commercial embodiment thereof. The apparatus is specifically designed and adapted for use in a foundry or similar establishment and serves as a means for mulling and conditioning molding sand preparatory to use of the latter in flasks during a casting operation. Briefly, the apparatus involves in its general organization a mulling bowl 10 within which there is centrally disposed a rotatable unitary sand mulling assembly. The latter comprises a central, rotatably mounted hub 12, a continuous series of three mulling elements in the form of horizontal wheels 14, and a continuous series of three deflector-like plows 16. The mulling wheels 14, as well as the plows 16, are carried on the outer peripheral region of the hub 12 and are equally spaced in a circumferential direction on arcs of 120. The wheels 14 are rotatably mounted on the hub 12 and thus are revolvable bodily about the vertical axis of the hub and also rotatable about their own individual vertical axes. The plows 16 are fixedly secured to the hub, the hub during drive or rotation of the mulling assembly as a whole. The apparatus also includes an air supply duct 18 for introducing air under pressure to the interior of the bowl 10 for sand-aeration and cooling purposes, a water supply pipe 20 for introducing water to the bowl for admixture with the sand, and an electric motor M which is operatively connected through the medium of a gear reduction device 22 to the aforesaid rotary sand mulling assembly. The apparatus is essentially of the batch type and is adapted to mull and condition successive batches of new or previously used molding sand. The latter may be periodically introduced into the bowl 10 through the open upper rim thereof by way of an endless conveyor or other means (not shown). The bowl is removably supported upon a base casting 24 which, in turn, is mounted on a lower main supporting frame 26.

More specifically and with particular reference to FIGS. 1 and 2, the bowl 10 is of composite nature and cylindrical design. It comprises an annular bottom wall 39, and a rubber-lined cylindrical side wall 32. The rubber liner of the side wall of the bowl is designated by the reference numeral 34 and is of an arcuate sectional nature. The bowl side wall 32 presents an open upper rim 36 which is provided with a narrow butwardly extending rim flange 38. The annular bottom wall 3%) has central opening 40. The bowl 10 is removably clamped to the base casting 24 by means of an annular series of spaced apart clamp assemblies 42. Each of these assemblies consists of a clamp lug 44 which is welded to the bowl side wall 32 at a point adjacent to the bottom rim thereof, a hook-like bowl clamping arm 46, and a cap screw 47 which projects through the clamping arm and is threadedly received in the associated clamp lug 44. The clamping arms of the clamp assemblies 42 are adapted to hook beneath a circular, depending, marginal rib 48 on the base casting 24 so that when the cap screws 47 are tightened, the adjacent portion of the bowl will be drawn downwardly hard against the base casting on which it securely seats.

The side wall 32 of the bowl 10 of the mulling apparatus is interrupted through an arcuate extent thereof to provide a discharge opening 50 which is adapted to be closed by a hinged arcuate door 52 having associated therewith a rubber liner 54 which constitutes a continuation of the side wall liner 34 when the door is in its closed position. The door 52 is hinged on a support 56 and is movable between open and closed positions with respect to the door opening 50 under the control of an air cylinder 58. The latter is hinged or pivotally mounted by means of laterally extending trunnions 60 on the side wall of the air cylinder. The trunnions are rotatably supported in a mounting block 62 which is pivoted at 6-4 to the support 56. The air cylinder 58 is provided with a plunger 66 which is operatively connected to the door by way of a toggle mechanism including a short link 68 and a long link 70. The short link 68 of the toggle mechanism is connected to a stationary bracket 72 on the bowl 10 and the long link is connected to the door 52. The air cylinder 58 is provided with lines 74 and 76 for plungeractuating fluid under pressure. From the above description, it will be understood that, when the plunger 66 is in its retracted position, the aforementioned toggle mechanism will be operated in such a manner as to pull the door 52 to an open position. An adjustable set screw and jam nut assembly 78 serves to determine the fully closed position of the door so that the arcuate rubber liner 54 may be accurately aligned circumferentially with the sectional rubber side wall liner 34. A vertically extending curved sand deflector plate 80 is positioned at one side of the discharge opening 50 and is secured at its vertical end edges by means of brackets 82 and 84 to adjacent portions of the bowl 1%. As will be described in greater detail presently, at the end of each batch operation when the door 52 is opened, the sand is ejected from the interior of the bowl under the influence of centrifugal force, the sand leaving the bowl in a generally tangential direction and impinging against the deflector plate 80.

As best shown in FIGS. 1 and 3, the rotary sand mulling assembly which, as previously stated, embodies the hub 12, the mulling wheels 14, and the plows 16, is rotatably mounted on a vertically extending pedestal 96 having an annular foot flange 91 which is fixedly connected to the inner marginal portion of the base casting 24 by means of an annular series of bolts 92. The pedestal projects upwards through and above the base casting. The latter is of irregular box-like design and is supported on the main supporting frame 26 by means of bracket extensions 94 which are connected to the main supporting frame by way of bolts .96. The base casting 24 embodies generally horizontal top and bottom walls 98 and 100. The top wall 98 of the base casting is provided with a laterally extending annular flange extension 101 which has formed thereon the marginal depending rib 48. The latter cooperates with the clamp assemblies 42 to hold the bowl 10 in position on the base casting 24 as previously described. The bottom wall 1% of the base casting is provided with a central opening 102 which is defined by a thickened rim region 104. The foot flange 91 of the pedestal 90 is clamped by the bolts 92 against the thickened rim region 104 of the bottom wall 100. The top wall 98 of the base casting 24 is provided with a central circular opening 106. The top wall rim portion which defines the central opening 106 embodies an upwardly and outwardly extending annular sand-restraining flange 168. The pedestal 90 projects upwardly through the opening 106 and extends well into the medial region of the interior of the bowl 10. The base casting 24 embodies a side wall 110 which is provided with'an air inlet opening 112 in communication with the air supply duct 18. A pivoted fluid-actuated damper 114 in the opening 112 serves to control flow of air under pressure through the duct 18. The inlet end'of the air supply duct 18 leads from the exhaust side of a suitable motor-driven blower (not shown). An air cylinder 115 is pivoted on a bracket 116 and has a plunger 118 which is operatively connected to a crank arm 120. The latter, in turn, is connected to the pivoted damper 114 and serves to swing the damper back and forth in respect to actuation of the air cylinder 115.

Still referring to FIG. 1, the lower main frame 26, on which the base casting 24 is supported, is of open boxlike design and carries the motor M and the gear reduction device 22. The motor M is connected by bolts 122 to the frame 26 while the gear reduction device 22 is provided with bracket supports 124 by means of which the device is suspended from the underneath side of the bottom wall 100 of the base casting 24. The bracket supports 124 are connected by bolts 126 to the bottom wall 100. The output shaft 128 of the motor M carries a multiple pulley assembly 130 and the input shaft 132 of the gear reduction device 22 is provided with a similar pulley assembly 134, the-two pulley assemblies being operatively connected together in driving relationship by multiple V-belts 136. The output element of the gear reduction device 22 is in the form of a gear 138, the outline of which appears in dotted lines in FIG. 1 and the hub portion 140 of which is rotatably journalled in upper and lower gear case end caps 142 and 144. The gear 138 is coaxial with the pedestal 90 thereabove and the hub portion 140 thereof is internally splined as at 145 for cooperation with the lower splined end portion 146 of a vertically disposed drive shaft 147 (see FIG. 3) which projects upwardly through the opening 102 and 106 and is centered in the pedestal 90 in a manner that will be described hereafter. The upper end of the drive shaft 147 is connected by a shear pin 148 to a drive cap 149 which, in turn, is operatively and drivably connected to the hub 12 in a manner that will become clear when the nature of the hub and its associated parts is better understood.

Referring now to FIGS. 1, 2 and 4, the hub 12 of the rotary sand mulling assembly of the mulling apparatus is of a composite nature and includes a casting 150 having the general shape characteristics of a truncated convex paraboloid of revolution of the type wherein the parabolic arc is revolved about an axis normal to the axis of the parabola and tangent to the parabola at its apex. The truncated upper portion of the casting 150 is surmounted by a sheet metal cone 152, the apex region of which is rounded as indicated at 154. The hub 12 as a whole thus takes on a mushroom-like appearance when considered in connection with the pedestal on which it is mounted. The entire upper surface of the hub 12 including the paraboloid section (casting and the cone section (cone 152) is polished to a high degree of smoothness to reduce the coefiicient of friction between the hub and the sand within the bowl 10, and thus reduce to a minimum any tendency for the sand to cling or stick to the upper surface of the hub. The partly paraboloidal and pantly conical contour of the upper surface of the hub 12 is so designed that the angle of repose of sand particles on any given point thereof will approach a zero angle when the hub is set into motion at a predetermined speed.

Inasmuch as any given are of a parabola may be revolved about any one of four axes of revolution, and inasmuch as consideration may be given to either the convex or the concave effect of such revolution of the.

arc, the arc is thus capable of producing eight forms of paraboloids of revolution. Only one type of paraboloid of revolution is applicable to the contour of the hub 12 herein, the particular paraboloid being shown as shaded in the graphical representation of FIG. 7.

In FIG. 7, the equation y =x defines the parabolic arc OA. Paraboloids of a convex nature are created when OAB is revolved about OB or about OC, and when OAC is revolved about 0C or CA. Paraboloids of a concave nature are created when OAB is revolved about CA or DC, and OAC is revolved about AB or OB. The first of these paraboloids, namely, when OAB is revolved about OB, represents the general shape of the peaked paraboloidal surface of the hub 12. The apex O of the parabola lies on the horizontal coordinate or abscissa OX, and this horizontal coordinate is the axis of revolution for the parabolic arc 0A.

The truncation or upper end region of the casting 1513 presents or forms a scalloped opening (see FIG. 4),

and this opening is normally closed by the sheet metal cone 152. The opening 160 is provided at the inner rim of a radial seating flange 162 at the upper end of the casting 150. The lower rim of the cone 152 seats within an annular recess 164 and abuts against a shoulder 166 so that the paraboloidal and conical surfaces of the hub merge gradually and present an unbroken contour.

As best'seen in FIG. 4, the underneath side of the convex generally paraboloidal hub 12 is formed with an integral annular air and water distribution manifold 170. The latter is of inwardly facing channel-shape in radial cross section and includes on the inner rim portion thereof an upturned circular lip 172 (see FIGS. 1 and 3). Three generally tangential but slightly curved radial branch passageways 174 lead outwardly from the distribution manifold, each passageway diverging slightly in transverse cross section. The passageways 174 terminate at the extreme periphery of the hub 12 in substantially rectangular discharge openings 176. Generally tangential but slightly curved vanes 178 are arranged in an annular series and extend outwards from the distribution manifold in diverging relationship in between adjacent passage- I ways 174 and terminate short of the periphery of the hub. The vanes 178 are formed as integral parts of the underneath side of the casting 150 of the hub 12. The direction of tangential extent of the passageways 1'74 and the vanes 178 is in the trailing direction when the hub is rotated.

Referring now to FIGS. 1, 2, 4 and 5, the three mulling wheels 14 are rotatably carried at the upper ends of three upstanding supporting arms 180 of tapered design. Such arms are integrally formed on the hub near the periphery thereof and are inclined upwardly andloutwardly with respect to the vertical. They are equally spaced on the hub and present streamlined contours which merge gradually into the contour of the upper surface of the hub. 12. The upper ends of the arms 180 terminate in enlarged heads 182. The latter have flat, horizontal, upwardly facing seating surfaces 184 for upstanding eccentric spindles 186 on which the bodies 188 of the mulling wheels are rotatably mounted. The spindles 186 may be secured in any desired position of eccentricity by means of clamping bolts 190. Spanner notches 191 in the lower ends of the spindles 186 facilitate eccentric adjustment of the spindles when the clamping bolts 199 are loosened.

Each wheel body 188 is in the form of a hollow disklike casting and embodies spaced apart upper and lower wheel walls 192 and 194. The lower walls 194 of the wheel bodies are substantially flat, while the upper walls 192 are in the form of para'boloids. An internal generally cylindrical wall 196 extends between the upper and lower walls 192 and 194 of each wheel body 188 and affords a wheel hub which is rotatably mounted on the associated spindle 186 by means of upper and lower ball bearing assemblies 198 and 20%. A spacer sleeve 202 is disposed between each set or pair of ball bearing assemblies 198 and 200 and the assemblies and spacer sleeve are sandwiched between a lock nut and washer assembly 204 and a wheel bearing cap 206. The bearing caps 206 of the wheels are secured in position on the lower walls 194 of the wheel bodies by screws 20%. Suitable lip-type oil seals 210 are provided for preventing egress of lubricating oil or grease from the cylindrical Walls 196 of the wheel bodies. Lubrication of the bearing assemblies 198 and 206 is effected by means of covered grease fittings 212 which are carried at the upper extremities of the paraboloidal upper walls 192.

The peripheral regions of the upper and lower wheel walls 192 and 194 of the wheel bodies 188 are connected by circumferentially spaced, vertically extending struts 214, as well as by cylindrical tire rims 216 which carry solid rubber or other elastomeric tires 218.

The wheels 14 are adapted to assume within the mulling bowl 10 peripheral positions wherein they are substantially tangential to the bowl side wall 32, although they do not necessarily touch or ride upon the side wall liner 34. Because the enlarged heads 182 of the arms 180 on which the wheels are mounted approximately overlie the peripheral edge of the hub 12, a major portion of each wheel 14 overhangs the peripheral edge of the hub. The adjustment whereby the eccentricity of the wheels 14 on the upper ends of the arms 180 is established so that the wheels are positioned in their substantially tangential relationship with respect to the bowl side wall 32, is made by loosening the clamping bolts 190 and then utilizing a spanner wrench in cooperation with the aforesaid spanner notches 191. After the adjustment has been made, the clamping bolts 190 are again tightened.

As shown in FIGS. 2 and 4, the three plows 16 are equally spaced about the periphery of the hub 12 and are positioned radially outwardly beyond the peripheral edge of the hub. Each plow is in the form of an assembly and comprises a plow proper 220 which is supported upon a plow holder 222. The plow holders are connected by way of bolts 224 to the underneath side of the hub 12 in the peripheral region of the latter and, consequently, they do not interrupt the smooth substantially paraboloidal contour of the hub. Each plow proper is in the form of a tapered steel blade having a wide forward or leading edge 226 and a relatively narrow rear or trailing edge 228. Each plow is positioned in front of the overhanging portion of an adjacent or associated mulling wheel 14. The general plane of each plow proper 220 is inclined forwardly and downwardly in the direction of rotation of the mulling assembly and at-an angle in the neighborhood of 20, and the elevation of the leading edge 226 is appreciably below the elevation of the adjacent mulling wheel 14. The elevation of the trailing edge 228 of each plow proper is slightly below the elevation of the adjacent mulling wheel 14. The elevation of the trailing edge 228 of each plow proper is slightly below the elevation of the adjacent mulling wheel 14 so that, upon rotation of the hub 12 in the direction indicated by the arrow in FIG. 2, sand is elevated into the path of the particular mulling wheel which immediately trails the plow proper, all in a manner and for a purpose that will be made clear when the operation of the present mulling apparatus is set forth.

Referring now to FIGS. 1 and 3, wherein the details of the pedestal 90 are best illustrated, the previously mentioned drive cap 149 is of dome-shaped configuration and embodies a lower lateral attachment flange 230 which is of scalloped design and is secured by means of bolts 232 to the upper enlarged end 233 of a hub mounting sleeve 234. The bolts 232 pass through the outwardly directed scalloped protuberances of the at tachment flange 230. Upper and lower roller bearing assemblies 236 and 238 are interposed between the mount ing sleeve 234 and the pedestal 90. A lower retainer ring 240 with a pair of lip-type lubricant seals 242 in associated relation with it is secured to the lower rim of the mounting sleeve 234 by screws 244. Similarly, an upper retainer ring 246 with a lip-type lubricant seal 248 in associated relation with it is secured to the upper rim of the mounting sleeve by screws 250.

In assembling the hub 12 upon the pedestal 90, the scalloped opening 160 in the casting 150 of the hub is caused to register with the scalloped attachment flange 239 of the drive cap 149 so that the seating flange 162 rests or seats upon the upper enlarged head 233 of the mounting sleeve 234. Bolts 252 are arranged in an annular series, project through the inwardly directed scallop protuberances of the seating flange 162 at the upper end of the hub casting 156, and serve to secure the hub 12 in position on the pedestal 90. As shown in FIG. 6, the annular series of bolts 252 which extend through the inwardly directed scallop protuberances of the flange 162, and the annular series of bolts 232 which extend through the outwardly directed scallop protu'berances of the attachment flange 230, are concentrically arranged, the two series of bolts being interposed between each other in alternate fashion, and the two flanges being coplanar and interlocked by reason of their scallop design.

As shown in FIG. 3, the lower region of the pedestal 99 is provided with a hole 260 and a grease line 262, having an exterior grease fitting 264 associated therewith, projects through this hole, extends upwardly in the pedestal, and communicates through a radial port 266 with the annular space which exists between the upper and lower seals 248 and 242. The extreme upper end of the grease line 262 is supported in an inturned flange 268 at the upper rim of the pedestal 90.

The previously-mentioned water supply pipe 20 communicates through an inlet opening 270 with the interior of a hollow, vertically elongated nozzle casting 272 having at its upper end an outwardly extending spout 274. The latter is in horizontal register with the interior of distribution manifold 17% immediately above the circular lip 172 (see FIGS. 3 and 4). The nozzle casting 272 is provided at its lower end with a foot 276 which is connected by bolts 273 to the foot flange 91 of the pedestal 90. By reason of the fact that the spout 274 is in horizontal register with the interior'of the distribution manifold 170, the three branch passageways 174 are successively brought into radial register with the spout during rotation of the hub 12 and, as a result, the water under pressure issuing from the spout is directed into these passageways while the water which issues from the spout at the intervening times when the passageways are out of register with the spout is collected within the distribution manifold and overflows by centrifugal force into the passageways. Water under pressure is supplied to the interior of the nozzle casting through the previously-mentioned watersupply pipe 20, the latter communicating with the interior of the casting through a suitable threaded fitting assembly 280.

Operation of the apparatus In the operation of the herein-described mulling apparatus, the mulling bowl is charged through the open upper rim 36 thereof with a batch of molding sand to be mulled and the prerequisite quantity of bonding agent, utilizing any suitable charging means, such as an overhead conveyor, or simply by batch dumping the sand and bonding agent into the bowl. Thereafter, upon energization of the electric motor M, the latter operates through the gear reduction device 22 to rotate the vertical drive shaft 147 and thus cause rotation of the paraboloidal hub 12 in the direction indicated by the arrow in FIG. 2. It will be understood, of course, that the air cylinder 58 will have previously been operated to swing the door 52 into seated relation with the discharge opening 51) in the cylindrical side wall 32 of the bowl 12 to the end that the elastomeric sectional side wall liner 34 and the elastomeric door liner 54 present a relatively smooth unbroken cylindrical inner surface.

Immediately after commencement of rotation of the hub 12, the air cylinder 115 will be operated to open the damper 114 to the desired degree in order to admit air under pressure through the air supply duct 18 and the air inlet opening 112 to the interior of the base casting 24.

The air supply duct 13 is, as previously indicated, operatively connected to the exhaust side of a suitable motor-driven blower, and it is contemplated that the blower will be energized at the time that the motor M is energized. Similarly, at this time and under the control of suitable valve means (not shown), water at a predetermined rate of flow is admittedto the interior of the nozzle casting 272.

The air which enters the base casting 24 through the air inlet opening 112 fills the annular space around the lower region of the pedestal 90 and then flows upwardly through the opening 106 until it encounters the central region of the underneath side of the hub 12. After impinging against the central region of the hub, the air under pressure is constrained to flow radially outwardly in all directions into the bowl interior. A portion of the air enters the inwardly opening channel-like distribution manifold 170 and flows radially outwardly through the branch passageways 174, such air comingling with such water as is discharged successively into the three passageways by the spout 274. A considerable amount of air is flung radially outwardly beneath the hub 12 by the action the wheels at specific distances from the side wall 32 in order to attain the most efficient mulling action. The wheels 14, during their revolution about the central vertical axis of the hub 12, rotate or spin about the axes of the spindles 186 upon which they are mounted, the spinning action of the wheels being occasioned by reason of the frictional differential encountered by the wheels at ditferent radial distances from the axis of revolution of the wheels about the rotational axis of the hub 12. In connection with such revolving and spinning of the wheels, the molding sand or other material undergoing mulling is squeezed or kneaded, so to speak, against the elastomeric side wall liner under the influence of the solid rubber tires 218. other and different function in their mulling operation, as will be made clear presently.

During rotation of the hub 12, the plows may be regarded as leading or proceeding the wheels 14, and in so leading them, they scoop up quantities of sand from the lower regions of the bowl 10, thus establishing voids or areas of sparse sand distribution. These voids or areas travel in a circular path, closely following the move tion of the curved vanes 178. The thus distributed air effects a cooling effect upon the sand within the mulling bowl 11), as by permeation of the sand mass.

Prior to setting the apparatus into operation, the eccentricity of the mulling wheels 14 with respect to the wheel-supporting arms 180 is adjusted in the manner previously described so that the mulling wheels 14 assume a nearly tangential relation with respect to the side wall 32 of the bowl 10 without actually touching the same and thus riding upon the rubber side wall liner. tion with the mulling of certain types of molding sand and also certain amounts of sand, it is expedient to posi- In connecment of the plows 16 in the peripheral regions of the bowl 10 and radially outwardly beyond the reach of the hub 12. It is to be noted that the discharge openings 176 of the branch passageways 174 open into the space in the bowl around the hub 12 at regions immediately trailing the traveling plows 16. Thus, air from the branch passageways 174 is introduced into and distributed uniformly throughout these traveling voids within the sand, as also is such water as is delivered to the branch passageways from the water spout 274.

Although the upper trailing edge 228 of each plow 16 lies a slight distance below the level of the mulling wheel 14 which trails it, the void established by the plow is of appreciably greater height than is the trailing edge 228 due to the scooping or lifting action of the plow which elevates the sand to a height greater than its own height. Each void is thus trailed by an adjacent oncoming mulling wheel 14 which rides through the elevated sand above the void, and by reason of its rotation, acts to compact the sand against the rubber-lined side wall 32. The elevated sand receives moisture from the adjacent void and the mixing of water with the sand in the presence of the surrounding air has a net effect of reducing the over-all temperature of the sand within the bowl 12 to from 15 to 25 above room temperature. By thus cooling the sand, theoperator, with full knowledge that there has been an appreciable temperature reduction and that eX- cessive evaporation of moisture will not take place within the sand, may then intelligently regulate the admission of water into the nozzle casting 272 for distribution throughout the bowl 111, as previously described.

Considering now the overall action of the rotating paraboloidal hub 12, the mulling wheels 14, and the plows 16, the net eifect produced by these moving elements within the bowl 10 is to establish a rotating torus of sand which extends around the bowl in the peripheral region thereof'at approximately the level of the mulling wheels 14. Each plow scoops up a quantity of sand as it travels in its circular path, leaving a shower of sand in its wake and into which the trailing or adjacent mulling wheel enters. The sand which spills sidewise from the plows onto the rotating paraboloidal hub 12 is again flung radially outwardly by centrifugal force to lend consistency to the torus. A combination of phenomena, including the action of the air which issues from the vanes 178, the action of the air and water which issue from the discharge openings 176 of the branch passageways 174 and the action of the sand which is flung from the paraboloidal hub 12, serves to give a folding type of swirling motion to the rotating torus by setting up helical eddy currents within the confines of the torus so that intimate mixing of the sand, water and bonding material is effectively attained. When the apparatus is thus in The wheels 14, however, have an- 1 1 operation, substantially all of the sand within the bowl 10 is maintained in suspension, much of it existing within the rotating torus.

At the conclusion of a sand mulling operation, the door 52 is swung open in the manner previously described by the admission of air to one end of the cylinder 58. The paraboloidal hub 12 is maintained in operation and the flinging action of all the rotating parts in associated relation with the rotating hub 12 causes the sand in the rotating torus, which at this time is not confined by the door liner 54, to be thrown outwardly through the discharge opening 50. Inasmuch as the torus has a rotating velocity in the direction of rotation of the paraboloidal hub 12, the sand passes through the door opening in a generally tangential direction with respect to the cylindrical side wall 32 of the bowl it) and impinges against the curved deflector plate 80, after which it may be collected in a suitable receptacle. By reason of the fact that the eccentricity of the three mulling wheels with respect to the enlarged heads (see FIG. is so adjusted that the wheels do not quite make tangential contact with the side wall liner 34, these wheels will pass the discharge opening 50 without interference from the edge portions of the bowl side wall which define the opening.

It is to be observed at this point that the paraboloidal contour of the central rotating hub 12 and the similar paraboloidal contour of the three mulling wheels 14, as well as the streamlined contour of the three plows 16, are such that sand is inhibited from clinging to the various surfaces of the hub assembly, and after a sand discharge operation has taken place, the hub and its adjuncts will be substantially free from adhering sand. The paraboloidal contours are such that, when the hub and wheels are rotating, the angle of repose of sand on any given point of these paraboloidal surfaces will approximate a zero angle and frictional forces, as well as sand tenacity, will be reduced to a minimum.

During the operation of the apparatus, the drive from the electric motor M, through the gear reduction device 22 and the drive shaft 147 to the paraboloidal hub 12 is effected through the shear pin 148 to the hub drive cap 149, and from thence, through the mating scalloped edges afforded by the attachment flange 230 and the opening 160 in the casting 150 of the paraboloidal hub 12. The mating scalloped and interlocking connection is substantially incapable of rupture but the shear pin is capable of rupture when the shaft is subjected to tortional effects which are beyond its modulus of tortional elasticity. Shocks of a minor nature may be assimilated by slight tortional twisting of the shaft within its elastic limit. However, complete jamming of the apparatus is made impossible by the shear factor of the shear pin 148.

The invention is not to be limited to the exact arrangement of parts shown in the accompanying drawings or described in this specification as various changes in the details of construction may be resorted to without departing from the spirit or scope of the invention. For example, the specific form of gear reduction device 22 illustrated and described herein is only exemplary of an operable power train drive from the electric motor M to the vertical drive shaft 147 for the paraboloidal hub 12. The illustrated form of drive, including the gear reduction device 22, does not necessarily represent a commercial embodiment of the driving mechanism. Therefore, only insofar as the invention has particularly been pointed out in the accompanying claims is the same to be limited.

Having thus described the invention what I claim as new and desire to secure by Letters Patent is:

l. A mulling apparatus of the character described comprising, in combination, a bowl adapted to receive therein a predetermined amount of the granular material to be mulled and including a bottom wall and an upstanding continuous cylindrical side wall, a mulling assembly mounted for rotation within said bowl about the central vertical axis of the bowl, said assembly comprising a comparatively large, circular central hub presenting a smooth upper face which is generally in the form of a peaked paraboloid of revolution of the type wherein the paraboloic arc is revolved about an axis normal to the axis of the parabola and tangent to the parabola at its apex, the peripheral rim region of the paraboloid being substantially horizontal and also spaced a comparatively small distance inwards from the bowl side wall, said assembly also comprising a mulling element eccentrically mounted on said hub, overlying the peripheral region thereof for movement bodily with the hub, adapted during travel in a circular path to squeeze the material between it and the side wall of the bowl and thus effect mulling of the material, and in the form of a horizontal wheel freely rotatable about a vertical axis which is fixed with respect .to said hub, said assembly additionally comprising a plow connected to and disposed outwards of the hub and adapted during a mulling operation to defiect upwards the material into the path of the mulling element and over the upper face of the hub, and power means for rotating the mulling assembly, said upper face of the hub being operative during a mulling operation and because of its particular shape forcibly to fling the superjacent material outwards and cause it to become denslfied against the bowl side wall.

2. A mulling apparatus of the character described comprising, in combination, a bowl adapted to receive therein a predetermined amount of the granular material to be mulled and including a bottom wall and an upstanding continuous cylindrical side wall, a mulling assembly mounted for rotation within said bowl about the central vertical axis of the bowl, said assembly comprising a comparatively large, circular, central hub presenting a smooth upper face which is generally in the form of a peaked paraboloid of revolution of the type wherein the parabolic arc is revolved about an axis normal to the axis of the parabola and tangent to the parabola at its apex, the peripheral rim region of the paraboloid being substantially horizontal and also spaced a comparatively small distance from the bowl side wall, said assembly also comprising a mulling element eccentrically mounted on said hub and overlying the peripheral region thereof for movement bodily with the hub and adapted during travel in a circular path to squeeze the material between it and the side wall of the bowl and thus effect mulling of the material, said mulling element being in the form of a horizontal wheel of disk-like design and presenting a smooth upper face which is generally in the form of a peaked paraboloid of revolution similar to the paraboloid which is presented by the upper face of the hub, said wheel being mounted on the hub for free rotation about a vertical axis which is fixed with respect to said hub, said mulling assembly comprising additionally a plow connected to and disposed outwards of the hub and adapted during a mulling operation to deflect upwards the material into the path of the mulling element and over the upper face of the hub, and power means for rotating the mulling assembly, said upper face of the hub being operative during a mulling operation and because of its particular shape forcibly to fling the superjacent material outwards and cause it to become densified against the bowl side wall.

3. A mulling apparatus of the character described comprising, in combination, a bowl adapted to receive therein a predetermined amount of the granular material to be mulled and including a bottom wall and an upstanding continuous cylindrical side wall, a mulling assembly mounted for rotation within the bowl about the central vertical axis of the bowl, said assembly comprising a comparatively large, circular, central hub presenting a smooth upper face which is generally in the form of a peaked paraboloid of revolution of the type wherein the parabolic arc is revolved about an axis normal to the axis of the parabola and tangent to the parabola at its apex, the peripheral rim region of the paraboloid being substantially horizontal and also spaced a small distance inwards from the bowl side wall, said assembly also comprising a plurality of equally and circumferentially spaced horizontal mulling wheels eccentrically mounted on said hub and overlying the peripheral region thereof for movement modily with the hub and in a circular path about the vertical axis of the bowl, said wheels being aproximately tangential to the bowl side wall but spaced a slight distance inwardly thereof so as to be out of contact therewith, said wheels being freely rotatable about respective vertical axes which are fixed with respect to the hub, each mulling wheel presenting a smooth upper face which is generally in the form of a peaked paraboloid of revolution similar to the paraboloid which is presented by the upper face of the hub, at least one half of each mulling wheel overhanging the peripheral region of the hub, said assembly comprised additionally a plow arrangement connected to and disposed outwards of the hub and adapted during a mulling operation to deflect upwards the material into the path of the mulling wheels and over the upper face of the hub, and power means for rotating the mulling assembly, said upper face of the hub being operative during a mulling operation and because of its particular shape forcibly to fiing the superjacent materal outwards and cause it to become densified against the bowl side wall.

4. A mulling apparatus of the character described comprising, in combination, a bowl adapted to receive therein a predetermined amount of the granular material to be mulled and including a bottom wall and an upstanding continuous cylindrical side wall, a mulling assembly mounted for rotation within the bowl about the central vertical axis of the bowl, said assembly comprising a comparatively large, circular, central hub presenting a smooth upper face which is generally in the form of a peaked paraboloid of revolution of the type wherein the parabolic arc'is revolved about an axis normal to the axis of the parabola and tangent to the parabola at its apex, the peripheral rim region of the paraboloid being substantially horizontal and also spaced a comparatively small distance inwards from the bowl side wall, said assembly also comprising a plurality of upstanding support arms on said hub projecting generally upwardly from the upper face of the hub, said arms being of smooth tapered design and having the contours of their lower end regions merging gradually with the contour of said upper face at their regions of juncture therewith, said arms being equally and circumferentially spaced about the axis of the hub, said assembly also comprising a horizontal mulling wheel mounted on the upper end of each supporting arm for individual and free rotation about a vertical axis which is fixed with respect to the hub, each wheel being approximately tangential to the bowl side wall but spaced a slight distance inwardly thereof so as to be out of contact with the side wall, said assembly also comprising a plow arrangement connected to and disposed outwards of the hub and adapted during a mulling operation to deflect upwards the material into the path of the mulling wheels and over the upper surface of the hub, and power means for rotating said mulling assembly, said upper face of the hub being operative during a mulling operation and because of its particular shape forcibly to fling the superjacent material outwards and cause it to become densified against the bowl side wall.

5. A mulling apparatus of the character described comprising, in combination, a bowl adapted to receive therein a predetermined amount of the granular material to be mulled and including a bottom wall and an upstanding continuous cylindrical side wall, a mulling assembly mounted for rotation within the bowl about the central vertical axis of the bowl, said assembly comprising a comparatively large, circular, central hub presenting a smooth upper face which is generally in the form of a peaked region of the paraboloid being substantially horizontal and also spaced a comparatively small distance inwards paraboloid of revolution of the type wherein the parathe peripheral rim region of the paraboloid being substan-' tially horizontal and also spaced a comparatively small distance from the bowl side wall, said assembly also comprising a plurality of upstanding supporting arms on said hub projecting generally upwardly from the upper face of the hub, said arms being of smooth tapered design and having the contours of their lower end regions merging gradually with the contour of said upper face at their regions of juncture therewith, said arms being equally and circumferentially spaced about the axis of the hub, said assembly also comprising a horizontal mulling wheel mounted on the upper end of each supporting arm for individual and free rotation about a vertical axis which is fixed with respect to the hub, each wheel being approximately tangential to the bowl side wall but spaced a slight distance inwardly thereof so as to be out of contact with the side wall, each mulling wheel presenting a smooth upper face which is generally in the form of a peaked paraboloid of revolution similar to the paraboloid which is presented by the upper face of the hub, said arms being inclined upwardly and outwardly away from the axis of rotation of the hub and having their upper ends terminating substantially in the upwardly extended cylindrical confines of the circular outer rim region of the hub whereby approximately one half of each mulling wheel overhangs the outer rim of the hub, said assembly also comprising a plow arrangement connected to and disposed outwards of the hub and adapted during a mulling operation to deflect upwards the material into the path of the mulling wheels and over the upper face of the hub, and power means for rotating said mulling assembly, said upper face of the hub being operative during a mulling operation and because of its particular shape forcibly to fling the superjacent material outwards and cause it to become densified against the bowl side wall.

6. A mulling apparatus of the character described comprising, in combination, a bowl adapted to receive therein a predetermined amount of the granular material to be mulled and including a bottom wall and an upstanding continuous cylindrical side wall, a mulling assembly mounted for rotation within the bowl about the central vertical axis of the bowl and adapted to be driven in one direction, said assembly comprising a comparatively large,

circular, central hub presenting a smooth upper face which is generally in the form of a peaked paraboloid of revolution of the type wherein the parabolic' arc is revolved about an axis normal to the axis of the parabola and tangent to the parabola at its apex, the peripheral rim from the bowl side wall, said assembly also comprising a plurality of equally and circumferentially spaced horizontal mulling wheels eccentrically mounted on said hub and overlying the peripheral region thereof for movement bodily with the hub and in a circular path about the vertical axis of the bowl, said wheels being approximately tangential to the bowl side wall but spaced a slight distance inwardly thereof so as to be out of contact therewith, said wheels being freely rotatable about respective vertical axes which are fixed but radially adjustable with respect to the hub, a portion of each mulling wheel overhanging the peripheral edge of the hub, said assembly also comprising a scoop-type plow fixedly mounted on said hub and positioned radially outwardly of the peripheral edge of the latter in front of the overhanging portion of each mulling wheel for elevating portions of the material into the path of movement of the associated wheel and over the upper face of the hub, and power-operated means for rotating said mulling assembly in said one direction, said upper face of the hub being operative during a mulling operation and because of its particular shape forcibly t0 fling the superjacent material outwards and cause it to become densified against the bowl side wall.

7. A mulling apparatus of the character described comprising, in combination, a bowl adapted to receive therein a predetermined amount of the granular material to be mulled and including a bottom wall and an upstanding continuous cylindrical side wall, a mulling assembly mounted for rotation within the bowl about the central vertical axis of the bowl and adapted to be driven in one direction, said assembly comprising a comparatively large, circular central hub presenting a smooth upper face which is generally in the form of a peaked paraboloid of revolution of the type wherein the parabolic arc is revolved about an axis normal to the axis of the parabola and tangent to the parabola at its apex, the peripheral rim region of the paraboloid being substantially horizontal and also spaced a comparatively small distance inwards from the bowl side wall, said assembly also comprising a plurality of upstanding supporting arms on said hub projecting generally upwardly in outwardly inclined fashion from the upper face of the hub at equally spaced eccentric regions thereof, said arms being of smooth tapered design and having the contours of their lower end regions merging gradually with the contour of said upper face and their regions of juncture therewith, the upper ends of said arms lying substantially in the upwardly extended cylindrical confines of the circular outer rim of the hub, said assembly also comprising a horizontal mulling wheel mounted on the upper end of each supporting arm for individual and free rotation about a vertical axis which is fixed with respect to the hub, each wheel being approximately tangential to the bowl side wall but spaced a slight distance inwardly thereof so as to be out of contact with the side wall, approximately one half of each wheel overhanging said circular outer rim of the hub, said assembly also comprising a scooptype plow fixedly mounted on said hub in front of each mulling wheel for elevating material into the path of movement of the wheel and over the upper face of the hub, and power means for rotating said mulling assembly in said one direction, said upper face of the hub being operative during a mulling operation and because of its shape forcibly to fling the superjacent material outwards and cause it to become densified against the bowl side wall.

8. A mulling apparatus of the character described comprising, in combination, a bowl adapted to receive therein the material to be mulled and including a bottom wall and an upstanding continuous cylindrical side wall, a mulling assembly mounted within the bowl, spaced above the bottom wall for rotation about the vertical central axis of the bowl, and adapted to be driven in one direction,

mulling elements eccentrically mountedon said hub and overhanging the peripherial region thereof for movement bodily with the hub and adapted during travel in a circular path to squeeze the material between them and the side wall of the bowl and thus efiect mulling of the material, the underneath side of said hub being formed with an annular inwardly opening channel-shaped distribution manifold having a plurality of generally radially extending branch passageways projecting generally radially outwardly therefrom and terminating in discharge openings adjacent to the periphery of the hub, portions of each mulling element lying outside of the extended cylindical confines of the hub, a scope-type plow fixedly secured to the hub and also lying outside the extended cylindrical confines of the hub adjacent to each discharge opening and in advance thereof with respect to the direction of rotation of the hub, there being one mulling element for each discharge opening positioned with its overhanging portion adjacent to and in arrears of the discharge opening with respect to the direction of rotation of the hub, means for introducing air under pressure to the interior of the bowl beneath said hub to establish a pressure head i said assembly comprising a central hub, a plurality of of air therebeneath, means for introducing water into said distribution channel and including a water spout in register with the channel, said plows serving, upon rotation of the hub in said direction, to elevate the material into the path of movement of the adjacent trailing mulling element while at the same time establishing a trailing void therebehind into which water and air from an adjacent discharge opening is forcibly introduced, and power means for rotating said hub in said one direction.

9. A mulling apparatus of the character described comprising, in combination, a bowl adapted to receive therein the material to be mulled and including a bottom wall and an upstanding continuous cylindrical side wall, a mulling assembly mounted within the bowl, spaced above the bottom wall for rotation about the vertical central axis of the bowl and adapted to be driven in one direction, said assembly comprising a central hub, a plurality of mulling wheels eccentrically mounted on said hub and overhanging the peripheral region thereof for move ment bodily with the hub and adapted during travel in a circular path to squeeze the material between them and the side wall of the bowl and thus effect mulling of the material, the underneath side of said hub being formed with an annular inwardly opening channel-shaped distribution manifold having a plurality of generally radially extending branch passageways projecting outwardly therefrom and terminating in discharge openings adjacent to the periphery of the hub, portions of each mulling wheel lying outside of the extended cylindrical confines of the-hub, a scoop-type plow fixedly secured to the hub and also lying outside the extended cylindrical confines of the hub adjacent to each discharge opening and in advance thereof with respect to the direction of rotation of the hub, there being one mulling wheel for each discharge opening position with its overhanging portion adjacent to and in arrears of the discharge opening with respect to the direction of rotation of the hub, each mulling wheel presenting a smooth upper face which 18 generally in the form of a peaked paraboloid of revolution of the type associated with the upper face of the hub, means for introducing air under pressure to the interior of the bowl beneath said hub to establish a pressure head of air therebeneath, means for introducing water into said distribution channel and including a water spout in register with the channel, said plows serving, upon rotation of the hub in said direction, to elevate the material into the path of movement of the adjacent trailing mulling element while at the same time establishing a trailing void therebehind into which water and air from an adjacent discharge opening is forcibly introduced, and power means for rotating said hub in said one direction.

10. In a mulling apparatus of the character described,

a base casting, a bowl supported upon said base casting, adapted to receive therein material to be mulled, and provided with a bottom wall having a central opening therein, a hollow tubular pedestal fixedly secured to Said base casting, projecting upwardly therefrom through said opening and extending into the bowl, a mounting sleeve rotatably supported upon said pedestal in surrounding relationship, a drive cap fixedly secured to the upper rim of the mounting sleeve and presenting a noncircular external drive surface, a mulling assembly secured to said mounting sleeve in driven relationship with respect thereto and including a sand impelling hub presenting an internal mating surface conformable in shape to the shape of said external drive surface and fitting thereagainst, a drive shaft extending upwardly through said pedestal, the upper end region of said drive shaft projecting into the drive cap, a shear pin projecting through said upper end region of the drive shaft and drive cap, and means for applying driving torque to the lower end of said drive shaft.

11. In a mulling apparatus of the character described, in combination, a base casting, a bowl adapted to receive therein a batch of sand to be mulled and provided with a bottom wall having a central opening therein, a hollow tubular pedestal fixedly secured to the base casting, projecting upwardly therefrom through said opening and ex tending into the bowl, a tubular mounting sleeve rotatably supported upon said pedestal in surrounding relationship and presenting an open upper circular rim, a drive cap including a crown portion and a radially outwardly extending rim flange which is supported upon said upper rim of the mounting sleeve, a mulling assembly secured to said mounting sleeve in driven relationship with respect thereto and including a sand-impelling hub having a radially inwardly extending rim flange which likewise is supported upon said upper rim of the mounting sleeve, interlocking drive means on saidrim flanges respectively, a series of clamping bolts securing the rim flange of the drive cap to the upper rim of the mounting sleeve, a series of clamping bolts securing the rim flange of the sand impelling hub to the upper rim of the mounting sleeve, a drive shaft projecting upwardly through said pedestal and into said drive cap, a shear pin projecting in radial fashion through said drive shaft and drive cap, and means for applying torque to the lower end of the drive shaft.

12. In a mulling apparatus of the character described,

in combination, a base casting a bowl adapted to receive therein a batch of sand to be mulled and provided with a bottom wall having a central opening therein, a hollow tubular pedestal fixedly secured to the base casting, projecting upwardly therefrom through the opening and extending into the bowl, a tubular mounting sleeve rotatably supported upon said pedestal in surrounding relationship and presenting an open upper circular rim, a drive cap including a crown portion and a radially outwardly extending rim flange of generally star shape scalloped design including radial scallop protuberances, a mulling assembly secured to said mounting sleeve in driven relationship with respect thereto and including a sand-impelling hub having a radially inwardly extending rim flange of mating star shape scalloped design including radial scallop protuberances, said rim flanges being supported upon said upper rim of the mounting sleeve in coplanar relationship with said scallop protuberances in interlocking relationship, a first series of clamping bolts projecting through the scallop protuberances of the rim flange of the drive cap for securing the latter to the mounting sleeve, a second series of clamping bolts projecting through the scallop protuberances of the rim flange of the sand-impelling hub for securing the latter to the mounting sleeve, a drive shaft projecting upwardly through said pedestal and into said drive cap, a shear pin projecting through said drive shaft and drive cap, and means for applying torque to the lower end of the drive shaft.

13. A mulling apparatus of the character described comprising, in combination, abowl adapted to receive therein a predetermined amount of the granular material to be mulled and including a bottom wall and an upstanding continuous cylindrical side wall, a mulling assembly mounted for rotation within said bowl about the central vertical axis thereof and adapted to be driven in one direction, said assembly comprising a comparatively large central hub presenting a smooth upper face the peripheral rim region of which is circular, extends substantially horizontally, and is spaced a comparatively small distance inwards of the bowl side wall, said assembly also comprising a mulling element eccentrically mounted on said hub, overlying the peripheral region thereof for movement bodily with the hub, and adapted during travel in a circular path to squeeze the material between it and the side wall of the'bowl and thus effect mulling of the material, the underneath surface of said hub being formed with a series of generally radially divergent vanes thereon, said vanes extending from the central region of the hub to the outer peripheral region, said mulling assembly additionally comprising a scoop-type plow fixedly mounted on the hub and positioned radially outwardly of the peripheral edge of the latter in front of the overhanging portion of the mulling element for elevating portions of the material into the path of movement of said element, means for introducing air under pressure to the interior of the bowl beneath said hub and at said central region for forcible centrifugal distribution by said vanes, and power means for rotating the mulling assembly in said one direction.

14. A mulling apparatus of the character described comprising, in combination, a bowl adapted to receive therein a predetermined amount of the granular 'material to be mulled and including a bottom wall and an upstanding continuous cylindrical side wall, a mulling assembly mounted for rotation within said bowl about the central vertical axis thereof and adapted to be driven in one direction, said assembly comprising a comparatively large central hub presenting a smooth upper face the peripheral rim region of which is circular, extends substantially horizontally, and is spaced a comparatively small distance inwards of 'the bowl side wall, said assembly also comprising a mulling element eccentrically mounted on said hub, overlying the peripheral region thereof for movement bodily with the hub, and adapted during travel in a circular path to squeeze the material between it and the side wall of the bowl and thus effect mulling of the material, the underneath surface of said hub being formed with a series of generally radially divergent vanes thereon, said vanes extending from the central region of the hub to the outer peripheral region and terminating short of both the central axis and the outer periphery of the hub, said vanes being substantially tangential at their inner ends to a common circle and the direction of tangential extent thereof being in the trailing direction when the hub is rotated, said mulling assembly additionally comprising a scoop-type plow fixedly mounted on the hub and positioned radially outwardly of the peripheral edge of the latter in front of the overhanging portion of the mulling element for elevating portions of the material into the path of movement of said element, means for introducing air under pressure to the interior of the bowl beneath said hub at said central region for forcible centrifugal distribution by said vanes, and power means for rotating the mulling assembly in said one direction.

15. A mulling apparatus of the character described comprising, in combination, a bowl adapted to receive therein a predetermined amount of the granular material to be mulled and including a bottom wall and an upstanding continuous cylindrical side wall, a mulling assembly mounted for rotation within said bowl about the central vertical axis thereof and adapted to be driven in one direction, said assembly comprising a comparatively large central hub presenting a smooth upper face the peripheral rim region of which is circular, extends substantially horizontally, and is spaced a comparatively small distance inwards of the bowl side wall, said assembly also comprising a mulling element eccentrically mounted on said hub, overlying the peripheral region thereof for movement bodily with the hub, and adapted during travel in a circular path to squeeze the material between it and the side wall of the bowl and thus eflfect mulling of the material, the underneath surface of said hub being formed with an annular inwardly opening channel-shaped distribution manifold having a plurality of radially extending branch passageways projecting outwardly therefrom and terminating in discharge openings adjacent to the periphery of .the hub, said mulling assembly additionally comprising a scoop-type plow fixedly mounted on the hub and positioned radially outwardly of the peripheral edge of the latter in front of the overhanging portion of the mulling element for elevating portions of the material into the path of movement of said element, means for introducing air under pressure tothe interior of the bowl beneath said hub to establish a pressure head of air therebeneath and within said distribution manifold for outward flow through said branch passageways, and power means for rotating the assembly in said one direction.

16. A mulling apparatus of the character described comprising, in combination, a bowl adapted to receive therein a predetermined amount of the granular material to be mulled and including a bottom wall and an upstanding continuous cylindrical side wall, a mulling assembly mounted for rotation within said bowl about the central vertical axis thereof and adapted to be driven in one direction, said assembly comprising a comparatively large central hub presenting a smooth upper face the peripheral rim region of which is circular, extends substantially horizontally, and is spaced a comparatively small distance inwards of the bowl side wall, said assembly also comprising a mulling element eccentrically mounted on said hub, overlying the peripheral region thereof for movement bodily with the hub, and adapted during travel in a circular path to squeeze the material between it and the side wall of the bowl and thus effect mulling of the material, the underneath surface of said hub being formed with an annular inwardly opening channel-shaped distribution manifold having a plurality of generally radially extending branch passageways projecting outwardly therefrom and terminating in discharge openings adjacent to the periphery of the hub, said underneath surface of said hub being also formed with a series of radially divergent vanes between each pair of adjacent branch passageways, said mulling assembly additionally comprising a scoop-type plow fixedly mounted on the hub and positioned radially outwardly of the peripheral edge of the latter in front of the overhanging portion of the mulling element for elevating portions of the material into the path of movement of said element, means for introducing air under pressure to the interior of said bowl beneath said hub to establish a pressure head of air within said distribution manifold for outward flow through said branch passageways and for forcible centrifugal distribution by said vanes, and power means for rotating the mulling assembly in said one direction.

17. A mulling apparatus of the character described comprising, in combination, a bowl adapted to receive therein the material to be mulled and including a bottom wall and an upstanding continuous cylindrical side wall, a mulling assembly mounted within the bowl, spaced above the bottom wall for rotation about the vertical central axis of the bowl and adapted to be rotated in one direction, said assembly comprising a comparatively large, circular, central hub, said assembly also comprising a plurality of mulling wheels eccentrically mounted on said hub and overhanging the peripheral region thereof for movement bodily with the hub and adapted during travel in a circular path to squeeze the material between them and the side wall of the bowl and thus effect mulling of the material, the underneath side of said hub being formed with an annular inwardly opening channel-shaped distribution manifold having a plurality of generally radially extending branch passageways projecting outwardly therefrom and terminating in discharge openings adjacent to .the periphery of the hub, portions of each mulling wheel lying outside of the extended cylindrical confines of the hub, said assembly also comprising a scoop-type plow fixedly secured to the hub and also lying outside the extended cylindrical confines of the hub adjacent to each discharge opening and in advance thereof with respect to the direction of rotation of the hub, there being one mulling wheel for each discharge opening positioned with its overhanging portion adjacent to and in arrears of the discharge opening with respect to the direction of rotation of the hub, means for introducing water into said distribution channel and including a water spout in register with the channel, said plows serving, upon rotation of the hub in said direction, to elevate the material into the path of movement of the adjacent trailing mulling element while at the same time establishing a trailing void therebehind into which water from an adjacent'discharge opening is 2.9 forcibly introduced, and power means for rotating said assembly in said one direction.

18. A mulling apparatus of the character described comprising, in combination, a bowl adapted to receive therein the material to be mulled and including a bottom wall and an upstanding continuous cylindrical side wall, a mulling assembly mounted within the bowl, spaced above the bottom wall for rotation about the vertical central axis of the bowl and adapted to be rotated in one direction, said assembly comprising a comparatively large, circular, central hub, said assembly also comprising a plurality of mulling wheels eccentrically mounted on said hub and overhanging the peripheral region thereof for movement bodily with the hub and adapted during travel in a circular path to squeeze the material between them and the side wall of the bowl and thus effect mulling of the material, the underneath side of said hub 'being formed with an annular inwardly opening channel-shaped distribution manifold having a plurality of generally radially extending branch passageways projecting outwardly therefrom and terminating in discharge openings adjacent to the periphery of the hub, portions of each mulling wheel lying outside of the extended cylindrical confines of the hub, said assembly also comprising a scoop-type plow fixedly secured to the hub and also lying outside the extended cylindrical confines of the hub adjacent to each discharge opening and in advance thereof with respect to the direction of rotation of the hub, there being one mulling wheel for each discharge opening positioned with its overhanging portion adjacent to and in arrears of the'discharge opening with respect to the direction of rotation of the hub, means for introducing air under pressure to the interior of the bowl beneath said hub to establish a pressure head of air therebeneath, means for introducing water into said distribution channel and including a water spout in register with the channel, said plows serving, upon rotation of the hub in said direction, to elevate the material into the path of movement of the adjacent trailing element while at the same time establishing a trailing void therebehind into which water and air from an adjacent discharge opening is forcibly introduced, and power means for rotating said assembly in said one direction.

19. An apparatus adapted to treat molding sand and the like comprising a bowl adapted to receive therein the sand to be treated and including a bottom wall and an upstanding continuous cylindrical side wall, an assembly mounted within the bowl, spaced above the bottom wall for rotation about the vertical central axis of the bowl, and adapted to be driven in one direction, said assembly comprising a central hub, the underneath side of said hub being formed with an annular inwardly opening channelshaped distribution manifold having a plurality of generally radially extending branch passageways projecting generally radially outwardly therefrom and terminating in discharge openings adjacent to the periphery of the hub, a scoop-type plow fixedly secured to the hub and lying outside the extended cylindrical confines of the hub adjacent to each discharge opening and in advance thereof with respect to the direction of rotation of the hub, means for introducing air under pressure to the interior of the bowl beneath said hub to establish a pressure head of air therebeneath, means for introducing water into said distribution channel and including a water spout in register with the channel, said plows serving, upon rotation of the hub in said one direction, to elevate the sand while at the same time establishing a trailing void therebehind into which water and air from an adjacent discharge opening is forcibly introduced, and power means for rotating said hub in said one direction.

20. An apparatus adapted to treat molding sand or the like comprising a bowl adapted to receive therein the sand to be treated and including a bottom wall and an upstanding continuous cylindrical side wall, an assembly mounted within the bowl, spaced above the bottom wall for rotation about the vertical central axis of the bowl and adapted to be driven in one direction, said assembly comprising a comparatively large, circular central hub, the underneath side of said hub being formed with an annular inwardly opening channel-shaped distribution manifold having a plurality of generally radially extending branch passageways projecting outwardly therefrom and terminating in discharge openings adjacent to the periphcry of the hub, a scoop-type plow fixedly secured to the hub and also lying outside the extended cylindrical confines of the hub adjacent to each discharge opening and in advance thereof with respect to the direction of rotation of the hub, means for introducing air under pressure to the interior of the bowl beneath said hub to establish a pressure head of air therebeneath, means for introducing water into said distribution channel and including a water spout in register with the channel, said plows serving, upon rotation of the hub in said direction, to elevate the sand while at the same time establishing a trailing void therebehind into which water and air from an adjacent discharge opening is forcibly introduced, and power means for rotating said hub in said one direction.

21. An apparatus adapted to treat molding sand or like granular material and comprising a bowl adapted to receive therein a predetermined amount of the sand to be treated and including a bottom wall and an upstanding continuous cylindrical side wall, an assembly mounted for rotation within said bowl about the central vertical axis thereof and adapted to be driven in one direction, said assembly comprising a comparatively large central hub presenting a smooth upper face the peripheral rim region of which is circular, extends substantially horizontally, and is spaced a comparatively small distance inwards of the bowl side wall, the underneath surface of said hub being formed with a series of generally radially divergent vanes thereon, said vanes extending from the central region of the hub to the outer peripheral region, said assembly additionally comprising a scoop-type plow fixedly mounted on the hub and positioned radially outwardly of the peripheral edge of the latter for elevating portions of the sand, means for introducing air under pressure to the interior of the bowl beneath said hub and at said central region for forcible centrifugal distribution by said vanes, and power means for rotating the assembly in said one direction.

22. An apparatus adapted to treat molding sand or the like and comprising a bowl adapted to receive therein a predetermined amount of the sand to be treated and including a bottom wall and an upstanding continuous cylindrical side wall, an assembly mounted' for rotation within said bowl about the central vertical axis thereof and adapted to be driven in one direction, said assembly comprising a comparatively large central hub presenting a smooth upper face the peripheral rim region of which is circular, extends substantially horizontally, and is spaced a comparatively small distance inwards of the bowl side wall, the underneath surface of said hub being formed with a series of generally radially divergent vanes thereon, said vanes extending from the central region of the hub to the outer peripheral region and terminating short ofboth the central'axis and the outer periphery of the hub, said vanes being substantially tangential at their inner ends to a common circle and the direction of tangential extent thereof being in the trailing direction when the hub is rotated, said assembly additionally comprising a scoop-type plow fixedly mounted on the hub and positioned radially outwardly of the peripheral edge of the latter for elevating portions of the sand, means for introducing air under pressure to the interior of the bowl beneath said hub at said central region for forcible centrifugal distribution by said vanes, and power means for rotating the assembly in said one direction.

23. An apparatus adapted to treat molding sand or the like and comprising a bowl adapted to receive therein a predetermined amount of sand to be treated and including a bottom wall and an upstanding continuous cylindrical side wall, an assembly mounted for rotation within 22 said bowl about the central vertical axis thereof and adapted to be driven in one direction, said assembly comprising a comparatively large central hub presenting a smooth upper face the peripheral rim region of which is circular, extends substantially horizontally, and is spaced a comparatively small distance inwards of the bowl side wall, the underneath surface of said hub being formed with an annular inwardly opening channel-shaped distribution manifold having a plurality of radially extending branch passageways projecting outwardly therefrom and terminating in discharge openings adjacent to the periphery of the hub, said assembly additionally comprising a scoop-type plow fixedly mounted on the hub and positioned radially outwardly of the peripheral edge of the latter for elevating portions of the sand, means for introducing air under pressure to the interior of the bowl beneath said hub to establish a pressure head of air therebeneath and within said distribution manifold for outward I flow through said branch passageways, and power means for rotating the assembly in said one direction.

24. An apparatus adapted to treat molding sand or the like and comprising a bowl adapted to receive therein a predetermined amount of the sand to be treated and including a bottom wall and an upstanding continuous cylindrical side wall, an assembly mounted for rotation within said bowl about the central vertical axis thereof and adapted to be driven in one direction, said assembly comprising a comparatively large central hub presenting a smooth upper face the peripheral rim region of which is circular, extends substantially horizontally, and is spaced a comparatively small distance inwards of the bowl side Wall, the underneath surface of said hub being formed with an annular inwardly opening channel-shaped distribution manifold having a plurality of generally radially extending branch passageways projecting outwardly therefrom and terminating in discharge openings adjacent to the periphery of the hub, said underneath surface of said hub being also formed with a series of radially divergent vanes between each pair of adjacent branch passageways, said assembly additionally comprising a scoop-type plow fixedly mounted on the hub and positioned radially outwardly ofthe peripheral edge of the latter for elevating portions of the sand, means for introducing air under pressure to the interior of said bowl beneath said hub to establish a pressure head of air within said distribution manifold for outward flow through said branch passageways and for forcible centrifugal distribution by said vanes, and power means for rotating the assembly in said one direction.

25. An apparatus adapted to treat molding sand or the like and comprising a bowl adapted to receive therein the sand to be treated and including a bottom wall and an upstanding continuous cylindrical side wall, an assembly mounted within the bowl, spaced above the bottom wall for rotation about the vertical central axis of the bowl and adapted to be rotated in one direction, said assembly comprising a comparatively large, circular, central hub, the underneath side of said hub being formed with an annular inwardly openingrchannel-shaped distribution manifold having a plurality of generally radially extending branch passageways projecting outwardly therefrom and terminating in discharge openings adjacent to the periphery of the hub, said assembly also comprising a scoop-type plow fixedly secured to the hub and also lying outside the extended cylindrical confines of the hub adjacent to each discharge opening and in advance thereof with respect to the direction of rotation of the hub, means for introducing water into said distribution channel and including a Water spout in register with the channel, said plows serving, upon rotation of the hub in said direction, to elevate the sand while at the same time establishing a trailing void therebehind into which water from an adjacent discharge opening is forcibly introduced, and power means for rotating said assembly in said one direction.

26. An apparatus adapted to treat molding sand or the like and comprising a bowl adapted to receive therein the sand-to be treated and including a bottom wall and an upstanding continuous cylindrical side wall, an assembly mounted within the bowl, spaced above the bottom wall for rotation about the vertical central axis of the bowl and adapted to be rotated in one direction, said assembly comprising a comparatively large, circular, central hub, the underneath side of said hub being formed with an annular, inwardly opening channel-shaped distribution manifold having a plurality of generally radially extending branch passageways projecting outwardly therefrom and terminating in discharge openings adjacent to the periphery of the hub, said assembly also comprising a scoop-type plow fixedly secured to the hub and also lying outside the extended cylindrical confines of the hub adjacent to each discharge opening and in advance thereof with respect to the direction of rotation of the hub, means for introducing air under pressure to the interior of the bowl beneath said hub to establish a pressure head of air therebeneath, means for introducing Water into said distribution channel and including a water spout in register with the channel, said plows serving, upon rotation of the hub in said direction, to elevate the sand while at the same time establishing a trailing void therebehind into which water and air from an adjacent discharge opening is forcibly introduced, and power means for rotating said assembly in said one direction.

References Cited by the Examiner UNITED STATES PATENTS 10/1930 Ullgren 259108 3/1949 Piper 24ll29 

21. AN APPARATUS ADAPTED TO TREAT MOLDING SAND OR LIKE GRANULAR MATERIAL AND COMPRISING A BOWL ADAPTED TO RECEIVE THEREIN A PREDETERMINED AMOUNT OF THE SAND TO BE TREATED AND INCLUDING A BOTTOM WALL AND AN UPSTANDING CONTINUOUS CYLINDRICAL SIDE WALL, AN ASSEMBLY MOUNTED FOR ROTATION WITHIN SAID BOWL ABOUT THE CENTRAL VERTICAL AXIS THEREOF AND ADAPTED TO BE DRIVEN IN ONE DIRECTION, SAID ASSEMBLY COMPOSING A COMPARATIVELY LARGE CENTRAL HUB PRESENTING A SMOOTH UPPER FACE THE PERIPHERAL RIM REGION OF WHICH IS CIRCULAR, EXTENDS SUBSTANTIALLY HORIZONTALLY, AND IS SPACED A COMPARATIVELY SMALL DISTANCE INWARDS OF THE BOWL SIDE WALL, THE UNDERNEATH SURFACE OF SAID HUB BEING FORMED WITH A SERIES OF GENERALLY RADIALLY DIVERGENT VANES THEREON, SAID VANES EXTENDING FROM THE CENTRAL REGION OF THE HUB TO THE OUTER PERIPHERAL REGION, SAID ASSEMBLY ADDITIONALLY COMPRISING A SCOOP-TYPE PLOW FIXEDLY MOUNTED ON THE HUB AND POSITIONED RADIALLY OUTWARDLY OF THE PERIPHERAL EDGE OF THE LATTER FOR ELEVATING PORTIONS OF THE SAND, MEANS FOR INTRODUCING AIR UNDER PRESSURE TO THE INTERIOR OF THE BOWL BENEATH SAID HUB AND AT SAID CENTRAL REGION FOR FORCIBLE CENTRIFUGAL DISTRIBUTION BY SAID VANES, AND POWER MEANS FOR ROTATING THE ASSEMBLY IN SAID ONE DIRECTION. 